This invention relates to precious-wood-faced sheets useful for decoration and boards having the same laminated thereupon (hereinafter referred to as decorative sheets and decorative boards). More particularly, it relates to decorative sheets and decorative boards useful as interior materials for houses and buildings (such as wall, ceiling and door facings), and as facing materials for furniture, cabinets, musical instruments and electrical appliances.
Recently, decorative boards using wood veneer as a base material have been used as ceiling and wall facings in houses and buildings, and various decorative sheets have also been used as facings for furniture and cabinets.
When a decorative wall or ceiling of this type is to be face-lifted, it is common practice to peel the bonded decorative board from the wall surface and replace it with a new decorative board. In this case, the veneer base material of the bonded decorative board is likely to break, with part of the broken material being left attached to the substrate. These attached veneer pieces must be removed before setting a new decorative board, making the replacement job rather cumbersome. In addition, the face lifting cost is increased because the total board must be replaced. A simpler and less costly method has also been adopted to avoid these disadvantages. This method involves bonding a new, thin decorative plastic sheet or decorative wall paper directly to the existing surface of a decorative board in use with only the outermost decorative wood veneer being peeled off, if necessary. However, this method also has disadvantages in that the beautiful grain of precious wood (such as Japanese cypress or zelkova) becomes hidden and the newly applied sheet or paper tends to become twisted, contracted or curled afterward, making uniform application over a wide area quite difficult.
Additionally, when using a decorative sheet as a facing of furniture and cabinets, the problem of poor dimensional stability and possible warpage after bonding arises.
Decorative boards composed of a base material, such as a plywood, and of a decorative sheet bonded thereto are commercially available. In this case, too, the poor dimensional stability of decorative sheet often causes defective products because of its elongation and shrinkage due to moisture absorption by the precious-wood veneer and supporting materials used.